Make builds default to quiet mode

Similar to the Linux kernel and perf add infrastructure to reduce the
amount of output tossed to a user during a build. Full build output
can be obtained with 'make V=1'

Builds go from:

make[1]: Leaving directory `/home/dsa/iproute2.git/lib'
make[1]: Entering directory `/home/dsa/iproute2.git/ip'
gcc -Wall -Wstrict-prototypes  -Wmissing-prototypes -Wmissing-declarations -Wold-style-definition -Wformat=2 -O2 -I../include -DRESOLVE_HOSTNAMES -DLIBDIR=\"/usr/lib\" -DCONFDIR=\"/etc/iproute2\" -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE    -c -o ip.o ip.c
gcc -Wall -Wstrict-prototypes  -Wmissing-prototypes -Wmissing-declarations -Wold-style-definition -Wformat=2 -O2 -I../include -DRESOLVE_HOSTNAMES -DLIBDIR=\"/usr/lib\" -DCONFDIR=\"/etc/iproute2\" -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE    -c -o ipaddress.o ipaddress.c

to:

...
    AR       libutil.a

ip
    CC       ip.o
    CC       ipaddress.o
...

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
diff --git a/bridge/Makefile b/bridge/Makefile
index 9800753..7203f70 100644
--- a/bridge/Makefile
+++ b/bridge/Makefile
@@ -9,6 +9,7 @@
 all: bridge
 
 bridge: $(BROBJ) $(LIBNETLINK) 
+	$(QUIET_LINK)$(CC) $^ $(LDFLAGS) $(LDLIBS) -o $@
 
 install: all
 	install -m 0755 bridge $(DESTDIR)$(SBINDIR)